Field of the Invention
The present invention relates to a power conversion apparatus.
Background Art
Since an insulated transformer for system interconnection is driven with a low frequency of several tens of Hz that is the same as a system frequency, there is a problem that a reduction in size and weight is difficult. In recent years, a solid-state transformer (SST) has been studied to apply to a high-voltage and high-power application. The SST has a high frequency transformer and a power circuit such as a DC/DC converter that outputs an alternating current of the system frequency by driving the high frequency transformer, and can substitute for a low frequency transformer of the related art. The high frequency transformer is driven with the high frequency of several tens of Hz to several hundreds of kHz and then it is possible to reduce the size of the high frequency transformer and to realize a significant reduction in size and weight compared to the low frequency transformer alone even if the power circuit and the high frequency transformer are combined.
In addition, the introduction of solar power generation is expanding worldwide as a power application for a system. A power conditioning system (PCS) outputting power of the solar power generation to a system by controlling power thereof has been known.
An inverter device for system interconnection that prevents an increase in noise or loss by substantially and constantly maintaining an operation frequency of a boost converter even if a voltage of DC input power is varied is described in JP-A-2001-209445.